RF powered plasma enhanced chemical vapor deposition reactor and methods of effecting plasma enhanced chemical vapor deposition

ABSTRACT

Plasma enhanced chemical vapor deposition (PECVD) reactors and methods of effecting the same are described. In accordance with a preferred implementation, a reaction chamber includes first and second electrodes operably associated therewith. A single RF power generator is connected to an RF power splitter which splits the RF power and applies the split power to both the first and second electrodes. Preferably, power which is applied to both electrodes is in accordance with a power ratio as between electrodes which is other than a 1:1 ratio. In accordance with one preferred aspect, the reaction chamber comprises part of a parallel plate PECVD system. In accordance with another preferred aspect, the reaction chamber comprises part of an inductive coil PECVD system. The power ratio is preferably adjustable and can be varied. One manner of effecting a power ratio adjustment is to vary respective electrode surface areas. Another manner of effecting the adjustment is to provide a power splitter which enables the output power thereof to be varied. PECVD processing methods are described as well.

CROSS REFERENCE TO RELATED APPLICATION

This patent application is a Continuation Application of U.S. patentapplication Ser. No. 09/026,042, filed Feb. 19, 1998, now U.S. Pat. No.6,395,128 entitled “RF Powered Plasma Enhanced Chemical Vapor DepositionReactor and Methods of Effecting Plasma Enhanced Chemical VaporDeposition,” naming Sujit Sharan, Gurtej S. Sandhu, Paul Smith and MeiChang as inventors, the disclosure of which is incorporated byreference. This application is related to U.S. Pat. No. 6,159,867, filedAug. 19, 1999, which is a divisional application of U.S. Pat. No.6,112,697, filed Feb. 19, 1998.

TECHNICAL FIELD

This invention relates to RF powered plasma enhanced chemical vapordeposition reactors and methods of effecting plasma enhanced chemicalvapor deposition.

BACKGROUND OF THE INVENTION

Semiconductor processing often involves the deposition of films orlayers over or on a semiconductor substrate surface which may or may nothave other layers already formed thereon. One manner of effecting thedeposition of such films or layers is through chemical vapor deposition(CVD). CVD involves a chemical reaction of vapor phase chemicals orreactants that contain the desired constituents to be deposited on thesubstrate or substrate surface. Reactant gases are introduced into areaction chamber or reactor and are decomposed and reacted at a heatedsurface to form the desired film or layer.

There are three major CVD processes which exist and which may beutilized to form the desired films or layers. These are: atmosphericpressure CVD (APCVD), low pressure CVD (LPCVD), and plasma enhanced CVD(PECVD). The former two processes (APCVD and LPCVD) are characterized bytheir pressure regimes and typically use thermal energy as the energyinput to effect desired chemical reactions. The latter process (PECVD)is characterized by its pressure regime and the method of energy input.

In PECVD systems, rather than relying on thermal energy to initiate andsustain chemical reactions, RF-induced glow discharge is used totransfer energy to the reactant gases. Such allows the substrate toremain at a lower temperature than the APCVD and LPCVD systems. Lowersubstrate temperatures are desirable in some instances because somesubstrates do not have the thermal stability to accept coating by theother methods. Other desirable characteristics include that depositionrates can be enhanced and films or layers with unique compositions andproperties can be produced. Furthermore, PECVD processes and systemsprovide other advantages such as good adhesion, low pinhole density,good step coverage, adequate electrical properties, and compatibilitywith fine-line pattern transfer processes.

One problem, however, associated with deposition processing includingPECVD processing stems from non-uniform film or layer coverage which canresult especially in high aspect ratio topographies. For example, aproblem known as “bread-loafing” or cusping can typically occur indeposition processing. Such normally involves undesirable non-uniformbuild-up of deposited material forming what appear as key hole spacesbetween features on a substrate. One prior art solution has been toconduct multiple depositions of very thin layers with intervening plasmaetching treatments. The intervening plasma etching serves to remove orcut away the cusps to form a more uniformly applied layer. Thereafter,repeated depositions and etchings are conducted until the desiredcoverage is achieved. It is desirable to improve upon the quality offilm or layer deposition in PECVD processes and reactors.

This invention grew out of concerns associated with improving PECVDprocessing systems and methods. This invention also grew out of concernsassociated with improving the advantages and characteristics associatedwith PECVD systems, including those advantages and characteristicsmentioned above.

SUMMARY OF THE INVENTION

Plasma enhanced chemical vapor deposition (PECVD) reactors and methodsof effecting the same are described. In accordance with a preferredimplementation, a reaction chamber includes first and second electrodesoperably associated therewith. A single RF power generator is connectedto an RF power splitter which splits the RF power and applies the splitpower to both the first and second electrodes. Preferably, power whichis applied to both electrodes is in accordance with a power ratio asbetween electrodes which is other than a 1:1 ratio. In accordance withone preferred aspect, the reaction chamber comprises part of a parallelplate PECVD system. In accordance with another preferred aspect, thereaction chamber comprises part of an inductive coil PECVD system. Thepower ratio is preferably adjustable and can be varied. One manner ofeffecting a power ratio adjustment is to vary respective electrodesurface areas. Another manner of effecting the adjustment is to providea power splitter which enables the output power thereof to be varied.PECVD processing methods are described as well.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below withreference to the following accompanying drawings.

FIG. 1 is a block diagram of a plasma enhanced chemical vapor deposition(PECVD) reactor system in accordance with preferred embodiments of thepresent invention.

FIG. 2 shows one implementation of one preferred PECVD reactor for usein the FIG. 1 system.

FIG. 3 shows another implementation of another preferred PECVD reactorfor use in the FIG. 1 system.

FIG. 4 shows one implementation of one preferred power splitter for usein the FIG. 1 system.

FIG. 5 shows another implementation of another preferred power splitterfor use in the FIG. 1 system.

FIG. 6 is a flow chart illustrating preferred processing methods for usein connection with the preferred embodiments of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This disclosure of the invention is submitted in furtherance of theconstitutional purposes of the U.S. Patent Laws “to promote the progressof science and useful arts” (Article 1, Section 8).

Referring to FIG. 1, a plasma enhanced chemical vapor deposition (PECVD)reactor system is shown in block diagram form generally at 10. System 10includes a gas supply unit 12, a chemical vapor deposition reactor 14,an RF power splitter 16 and an RF power generator 18.

Gas supply unit 12 can supply one or more gaseous reactants into reactor14 for processing in accordance with the invention. Typically, suchsystems use an RF-induced glow discharge to transfer energy into thereactant gases. Subsequently, free electrons are created within thedischarge region which gain energy so that when they collide with gasmolecules, gas-phase dissociation and ionization of the reactant gasesoccurs. Accordingly, energetic species are then absorbed on a workpieceor substrate.

PECVD reactor 14 defines a processing chamber or volume interiorly ofwhich processing takes place in accordance with the invention. In afirst preferred implementation, reactor 14 comprises a parallel platereactor. Such parallel plate reactor can be configured to process onlyone semiconductor workpiece or wafer. Alternately, such reactor can beconfigured to process more than one semiconductor workpiece or wafer. Ina second preferred implementation, reactor 14 comprises an inductivecoil PECVD reactor. Both preferred implementations are discussed belowin more detail in connection with FIGS. 2 and 3.

Referring still to FIG. 1, RF power splitter 16 in the illustrated andpreferred embodiments splits or otherwise divides RF input power whichis provided by RF power generator 18 into RF power components which arethereafter used to power separate reactor electrodes. In a preferredimplementation, such power is split or divided in accordance with aselected power ratio which can be manipulated by an operator of thesystem. Preferably, such ratio is one which is other than a direct 1:1ratio. Such split or divided power is subsequently applied via lines orterminals 15, 17 to individual electrodes comprising a part of reactor14, as will be described below.

Referring to FIG. 2, a PECVD reactor according to a first preferredimplementation is set forth generally at 20. Reactor 20 preferablycomprises a capacitive parallel plate reactor which may or may not beconfigured to process more than one workpiece or wafer. Preferably,reactor 20 defines a processing chamber 21 which includes a firstelectrode 22 disposed internally thereof. Electrode 22 is configured forsupporting at least one semiconductor workpiece in the form ofsemiconductor wafer W. The term “supporting” as such is used in thisdocument and in connection with the first electrode in each of theembodiments is intended to mean holding or positioning one or moresemiconductor workpieces in a desired orientation so that chemical vapordeposition can take place. Accordingly, semiconductor workpieces can besupported, held or otherwise positioned in orientations other than theshown horizontal position. Moreover, although the invention is discussedin the context of a system which includes only two electrodes, it is tobe understood that the invented reactors and methods can find use insystems which are not necessarily limited to only two electrodes. Firstelectrode 22 includes a first electrode surface area 24 upon which waferW rests for processing in accordance with the invention. First electrode22, in the illustrated and preferred embodiment, is a susceptor whichsupports the workpiece. Processing chamber 21 includes a secondelectrode 26 which is disposed internally thereof. A gap exists betweenthe electrodes such that the electrodes are suitably spaced from oneanother. In the illustrated and preferred embodiment, second electrode26 constitutes a shower head electrode which is positioned operablyadjacent the susceptor and configured to provide gaseous reactants intothe chamber from gas supply unit 12 (FIG. 1). Gaseous reactants can,however, be introduced into the reactor in other ways. Preferably,second electrode 26 defines a second electrode surface area 28 which isdifferent from and preferably smaller than first electrode surface area24. That is, first electrode surface area 24 is larger than the secondelectrode surface area 28. Such surface area differential between thefirst and second electrodes enables an RF power differential to bedeveloped as between the electrodes using only a single RF power source.Such will become apparent from the discussion below.

Referring still to FIG. 2, lines 15 and 17 are respectively operablyconnected to first and second electrodes 22, 26. Such lines connect RFpower generator 18 (FIG. 1) to the respective electrodes through RFpower splitter 16 which, for the purpose of the ongoing discussion, isoperatively interposed between the RF power generator and both thesusceptor and the shower head electrodes. Preferably, RF power generator18 comprises a single generator power source which is operativelyassociated with the processing chamber and configured to provide RFpower to the RF power splitter which, in turn, provides RF power to boththe susceptor and the shower head according to a selected power ratiowhich is discussed below in more detail. Such represents a noveldeparture from prior PECVD reactors wherein only the shower headelectrode was powered by an RF power source with the susceptor electrodebeing grounded. The illustrated single RF power generator is preferablyconfigured to provide RF power to the electrodes which is effective toboth develop a plasma processing environment within the processingchamber and provide a desired bias relative to the semiconductorworkpiece. For example, maintaining the electrodes at the preferredpower differential facilitates acceleration of ions or ionic speciestoward the subject workpiece or wafer which enhances conformal coverage,particularly in high aspect ratio topographies. Furthermore, greateruniformity in film or layer composition, as well as greater film orlayer purity levels are possible.

Referring to FIG. 3, and in accordance with another preferredimplementation of the invention, a different type of PECVD reactor 30 isset forth. Such reactor comprises an inductive coil PECVD reactor.Reactor 30 comprises a processing chamber 31 interiorly of whichchemical vapor deposition processing can take place in accordance withthe invention. A first electrode 32 is disposed internally of thereactor and is configured for supporting at least one semiconductorworkpiece, such as wafer W thereon. First electrode 32 is powered by thepreferred single RF power generator 18 (FIG. 1). It is possible for morethan one wafer to be processed in accordance with the invention. Asecond electrode 34 is provided externally of processing chamber 31 andcomprises a plurality of coils which are powered by the same preferredsingle RF power generator.

Referring to both FIGS. 2 and 3, such comprise PECVD reactors whichinclude respective electrodes both of which are powered by a single RFpower generator or supply. According to a first implementation, bothelectrodes are disposed internally of the processing chamber (FIG. 2).According to second preferred implementation, at least one of theelectrodes is disposed externally of the processing chamber (FIG. 3).Both electrodes in both preferred implementations are powered from andby a single RF powered generator, such as generator 18 in FIG. 1. Asmentioned above, this represents a novel departure from previous PECVDreactors where both electrodes were not powered with RF power from acommon, single RF power source.

Referring to FIG. 4, a preferred RF power splitter is set forthgenerally at 36. Power splitter 36 in the illustrated and preferredembodiment comprises a transformer 38 which includes an input side orprimary windings 40 and an output side or secondary windings 42. Inputside 40 is operatively coupled or connected to RF power generator 18(FIG. 1) via a coaxial cable 44 and receives power generated thereby.Output side 42 includes at least two output terminals 15, 17 which areoperatively coupled or connected to respective first and secondelectrodes 22, 26 (in the FIG. 2 PECVD reactor) or first and secondelectrodes 32, 34 (in the FIG. 3 PECVD reactor). In a preferredimplementation, the output side has no more than two terminals, and thefirst and second electrodes constitute the only processing chamberelectrodes which are powered thereby. Power splitter 36 splits inputpower provided by power generator 18 into first and second powercomponents which are thereafter provided to the respective electrodes.The output side of the preferred transformer provides power to each ofthe first and second electrodes in accordance with a selected powerratio which is discussed below. A suitable matching network 46 isprovided for impedance matching purposes. Such networks typicallyinclude various capacitative and inductive components which areconfigured for impedance matching. Such are represented in block diagramform in box 46.

In accordance with a preferred aspect of the invention, RF powersplitter 36 comprises a center tapped transformer in which the outputpower provided to the respective first and second electrodes issubstantially equal in magnitude. Such is desirable when power splitter36 is used in connection with the PECVD reactor of FIG. 2. In suchcircumstances, it has been found that the ratio of power which isapplied to the electrodes is related to surface areas 24, 28 ofelectrodes 22, 26. Hence, by changing or manipulating the subjectsurface areas, one can manipulate or select the power ratio and affectthe magnitudes of the first and second power components which are “seen”by the respective electrodes to which such power components are applied.In the illustrated and preferred embodiment, such surface areas aredifferent from one another, with the susceptor surface area being largerthan the shower head surface area. Such enables a power differential tobe developed according to a definable relationship. Such relationshipconsists of a predefined relative magnitude which is directlyproportional to the inverse ratio of the 4th power of the areas of theelectrodes. Put another way, by varying the relative surface area ratiosas between the susceptor and shower head, a variation in power appliedthereto can be effectuated. In the illustrated and preferred embodiment,second electrode or shower head 26 has a surface area which is less thanor smaller than the surface area of the first electrode or susceptor 22.Such results in a higher magnitude of power being applied to the showerhead than is applied to the susceptor. This advantageously allowsdeposition of reactants introduced into chamber 21 in a preferred mannerby causing highly energetic species to be drawn toward and in thedirection of the electrode supporting the workpiece.

Referring to FIG. 5, an alternate preferred power splitter is set forthgenerally at 36 a. Such alternate preferred power splitter enables thedesired power differential to be developed without regard to andindependently of the surface area ratios between the subject electrodes,whether such electrodes be those associated with the FIG. 2 reactor orthe FIG. 3 reactor. Like numbers from the first described power splitterare utilized where appropriate, with differences being indicated withthe suffix “a” or with different numerals. Accordingly, power splitter36 a comprises an input side 40 which is operatively coupled with RFgenerator 18 (FIG. 1) and an output side 42 a which is operativelycoupled with one of the preferred reactors 20, 30. Such enables, butdoes not require reactor 20 of FIG. 2 to have a susceptor electrode anda shower head electrode with respective surface areas which are morenearly equal. Power splitter 36 a advantageously allows the selectedpower ratio to be adjusted in a manner which varies the power suppliedto the electrodes. Accordingly, and in the illustrated and preferredembodiment, the RF power splitter comprises a transformer having aplurality of secondary windings 42 a. Such are desirably variablygroundable as is indicated at 48.

Referring still to FIG. 5 and for illustrative purposes only, outputside 42 a is shown as comprising nine windings. By selectively groundingdifferent windings or coils, different ratios of power are provided tothe shower head and susceptor electrodes. More specifically for example,if the number 2 coil or winding is grounded as shown, then the firstelectrode, either electrode 22 (FIG. 2) or 32 (FIG. 3) receives twoninths ({fraction (2/9)}) or 22.2% of the input power from the powergenerator. Accordingly, the second electrode, either electrode 26 (FIG.2) or 34 (FIG. 3) receives seven ninths ({fraction (7/9)}) or 77.8% ofthe input power. Relatedly, if the number 7 coil or winding is grounded,the distribution of power is reversed, i.e. the first electrode receivesseven ninths ({fraction (7/9)}) of the input power and the secondelectrode receives two ninths ({fraction (2/9)}) of the input power. Assuch, the provision of power to the preferred electrodes can be variedto accommodate different processing regimes. In the illustrated andpreferred FIG. 5 embodiment, power splitter 36 a is able to be adjustedby an end user for varying the selected power ratio to accommodatedifferent processing regimes. Such processing regimes preferably providea greater quanta of power to the second electrode rather than the firstelectrode. Alternately, the power provided to the electrode which isclosest in proximity to the semiconductor workpiece is less than thepower provided to the electrode which is spaced apart from suchworkpiece.

Accordingly, two separate and preferred power splitters have beendescribed. The first of which (FIG. 4) is advantageous for producingoutput power having magnitudes which are substantially the same. Suchpower splitter is suited for use in reactors, such as reactor 20 of FIG.2 in which the ultimate magnitude of power supplied to the illustratedelectrodes can be adjusted by varying the surface area ratios of thesubject electrodes. Such power splitter may also be used in connectionwith reactor 30. Alternately, and equally as preferred, a power splitter36 a (FIG. 5) allows for the output power to be variably adjusted to aselected power ratio which is suitable for use in reactors, such asreactor 20 of FIG. 2, in which electrodes do not have or are notrequired to have a meaningful variance between the electrode surfaceareas. Additionally, such power splitter can be and preferably isutilized in connection with reactor 30 of FIG. 3.

Referring to FIG. 6, a representative flow chart of a preferred methodof processing semiconductor workpieces in connection with the abovedescribed reactors is set forth generally at 100. The preferredmethodology involves first at step 110 placing a semiconductor workpiecein a selected one of the above-described PECVD reactors. According to apreferred implementation, a susceptor is provided for supporting theworkpiece internally of the processing chamber. In accordance with theFIG. 2 embodiment, a shower head electrode 26 is provided operablyadjacent the susceptor and is configured for providing gaseous reactantsinto chamber. According to the FIG. 3 embodiment, at least one of thereactor electrodes is disposed externally of the chamber. At step 112,gaseous reactants are provided into the reactor chamber whereupon, atstep 114, RF power from the preferred single or common RF power sourceis provided. At step 116, the provided RF power is split into first andsecond power components which are selectively provided to the respectiveelectrodes discussed above. For example, a first power component at step118 is applied to a first of the electrodes. At step 120, a second ofthe power components is applied to a second of the electrodes.Preferably, the applied power components are different from one anotherwith such difference stemming from either a variation in electrodesurface areas (FIG. 2) or a variably selectable grounding of thesecondary or output side 42 a (FIG. 5) of power splitter 36 a. Accordingto a preferred implementation, a transformer output coil, other than thecenter coil, can be selectively grounded for varying the relativemagnitudes of the power components. Such is indicated as an optionalstep 122 wherein an individual user may select a desired power ratio asbetween reactor electrodes. At processing step 124, and with the desiredpower ratio being applied to the selected electrodes, the semiconductorworkpiece is processed to effect chemical vapor deposition thereupon. Atstep 126, processing is complete and a next workpiece may be processedin accordance with the above description.

In compliance with the statute, the invention has been described inlanguage more or less specific as to structural and methodical features.It is to be understood, however, that the invention is not limited tothe specific features shown and described, since the means hereindisclosed comprise preferred forms of putting the invention into effect.The invention is, therefore, claimed in any of its forms ormodifications within the proper scope of the appended claimsappropriately interpreted in accordance with the doctrine ofequivalents.

What is claimed is:
 1. A capacitive plasma enhanced chemical vapordeposition reactor comprising: a susceptor electrode configured tosupport at least one semiconductor workpiece, the susceptor electrodecomprising a first surface area A₁; a shower head electrode operablyadjacent the susceptor electrode and configured to provide gaseousreactants, the shower head electrode comprising a second surface area A₂which is less than the first surface area A₁; a single RF powergenerator operatively coupled with the susceptor electrode and theshower head electrode and configured to provide RF power theretoeffective to develop a plasma processing environment and a desired biasrelative to the semiconductor workpiece; and an RF power splittercomprising a transformer having a primary winding and a separatesecondary winding, the primary winding coupled to the RF power generatorand the secondary winding coupled to both the susceptor electrode andthe shower head electrode, the RF power splitter configured to providepower from the RF power generator to both the susceptor and the showerhead electrode at a selected power ratio between the susceptor electrodeand the shower head electrode, wherein the selected power ratio is afunction of an inverse of a surface area ratio A₁/A₂.
 2. The plasmaenhanced chemical vapor deposition reactor of claim 1, wherein theselected power ratio is other than a 1:1 ratio.
 3. The plasma enhancedchemical vapor deposition reactor of claim 1, wherein the RF powersplitter comprises a transformer including a center tapped secondarywinding having at least two output terminals, individual outputterminals being connected to a respective one of the susceptor electrodeand the shower head electrode.
 4. The plasma enhanced chemical vapordeposition reactor of claim 1, wherein the selected power ratio isadjustable.
 5. The plasma enhanced chemical vapor deposition reactor ofclaim 1, wherein the RF power splitter comprises a transformer having aplurality of variably groundable secondary windings for changing theselected power ratio.
 6. The plasma enhanced chemical vapor depositionreactor of claim 1, wherein he RF power splitter comprises a pluralityof variably groundable secondary windings for adjusting the selectedpower ratio.
 7. A capacitive plasma enhanced chemical vapor depositionreactor comprising: a processing chamber; a susceptor electrode withinthe chamber configured to support at least one semiconductor workpiece,the susceptor electrode comprising a first surface area A₁; a showerhead electrode within the chamber operably adjacent the susceptorelectrode and configured to provide gaseous reactants into the chamber,the shower head electrode comprising a second surface area A₂ which isless than the first surface area A₁; a single RF power generatoroperatively coupled with the susceptor electrode and the shower headelectrode and configured to provide RF power thereto effective todevelop a plasma processing environment within the chamber and a desiredbias relative to the semiconductor workpiece; and an RF power splittercomprising a transformer having a primary winding and a separatesecondary winding, the primary winding coupled to the RF power generatorand the secondary winding coupled to both the susceptor electrode andthe shower head electrode, the RF power splitter configured to providepower from the RF power generator to both the susceptor and the showerhead electrode at a selected power ratio between the susceptor electrodeand the shower head electrode, wherein the selected power ratio is afunction of a surface area ratio A₁/A₂, wherein; the RF power splittercomprises a transformer including a center tapped secondary winding; andthe selected power ratio applies RF power to the showerhead electrodeproportional to (A₁/A₂)⁴.
 8. A parallel plate plasma enhanced chemicalvapor deposition reactor comprising: a susceptor electrode configured tosupport at least one semiconductor workpiece, the susceptor electrodecomprising a first surface area A₁; a shower head electrode configuredto provide reactants, the shower head electrode comprising a secondsurface area A₂ which is less than the first surface area A₁; and asingle RF power source operatively coupled to both the shower headelectrode and the susceptor electrode and configured to provide RF powerto each electrode proportional to an inverse ratio of areas of theshower head and susceptor electrode and effective to develop a desiredbias relative to a semiconductor workpiece supported by the susceptorelectrode and to develop a plasma processing environment.
 9. A parallelplate plasma enhanced chemical vapor deposition reactor comprising: aprocessing chamber; a susceptor electrode in the chamber and configuredto support at least one semiconductor workpiece, the susceptor electrodecomprising a first surface area A₁; a shower head electrode in thechamber and configured to provide reactants into the chamber, the showerhead electrode comprising a second surface area A₂ which is less thanthe first surface area A₁; and a single RF power source operativelycoupled to both the shower head electrode and the susceptor electrodeand configured to provide RF power to each electrode according to apredefined relative magnitude effective to develop a desired biasrelative to a semiconductor workpiece supported by the susceptorelectrode and to develop a plasma processing environment within theprocessing chamber, wherein the predefined relative magnitude isdirectly proportional to the inverse ratio of the 4th power of the areasof the electrodes.
 10. A parallel plate plasma enhanced chemical vapordeposition reactor comprising: a processing chamber; a susceptorelectrode in the chamber and configured to support at least onesemiconductor workpiece, the susceptor electrode comprising a firstsurface area A₁; a shower head electrode in the chamber and configuredto provide reactants into the chamber, the shower head electrodecomprising a second surface area A₂ which is less than the first surfacearea A₁; and a single RF power source operatively coupled to both theshower head electrode and the susceptor electrode and configured toprovide RF power to each electrode according to a predefined relativemagnitude effective to develop a desired bias relative to asemiconductor workpiece supported by the susceptor electrode and todevelop a plasma processing environment within the processing chamber,wherein the single RF power source is configured to apply RF power tothe showerhead electrode proportional to (A₁/A₂)⁴.
 11. A parallel plateplasma enhanced chemical vapor deposition reactor comprising: asusceptor electrode configured to support at least one semiconductorworkpiece, the susceptor electrode having a susceptor surface area A₁; ashower head electrode operably adjacent the susceptor electrode andconfigured to provide gaseous reactants, the shower head electrodehaving a shower head surface area A₂ which is smaller than the susceptorelectrode surface area A₁; a single RF power generator operativelyassociated with the susceptor and showerhead electrodes and configuredto provide RF power; and a transformer having an input side and aseparate, tapped secondary having no more than two output terminals, theinput side being operably connected with and capable of receiving RFpower from the RF power generator, and individual respective outputterminals being connected with the susceptor electrode and the showerhead electrode and configured to provide RF power to each electrode at aselected power ratio which is a function of an inverse of a ratio of theareas of the electrodes.
 12. A parallel plate plasma enhanced chemicalvapor deposition reactor comprising; a processing chamber; a susceptorelectrode within the chamber configured to support at least onesemiconductor workpiece, the susceptor electrode having a susceptorsurface area A₁; a shower head electrode within the chamber operablyadjacent the susceptor electrode and configured to provide gaseousreactants into the chamber, the shower head electrode having a showerhead surface area A₂ which is smaller than the susceptor electrodesurface area A₁; a single RF power generator operatively associated withthe processing chamber and configured to provide RF power; and atransformer having an input side and a separate, tapped secondary havingno more than two output terminals, the input side being operablyconnected with and capable of receiving RF power from the RF powergenerator, and individual respective output terminals being connectedwith the susceptor electrode and the shower head electrode andconfigured to provide RF power to each electrode at a selected powerratio which is a function of a ratio of the areas of the electrodeswherein the transformer is configured to apply RF power to theshowerhead electrode proportional to (A₁/A₂)⁴.
 13. A parallel plateplasma enhanced chemical vapor deposition reactor comprising: aprocessing chamber; a susceptor electrode within the chamber configuredto support at least one semiconductor workpiece, the susceptor electrodehaving a susceptor surface area A₁; a shower head electrode within thechamber operably adjacent the susceptor electrode and configured toprovide gaseous reactants into the chamber, the shower head electrodehaving a shower head surface area A₂ which is smaller than the susceptorelectrode surface area A₁; a single RF power generator operativelyassociated with the processing chamber and configured to provide RFpower; and a transformer having an input side and a separate, tappedsecondary having no more than two output terminals, the input side beingoperably connected with and capable of receiving RF power from the RFpower generator, and individual respective output terminals beingconnected with the susceptor electrode and the shower head electrode andconfigured to provide RF power to each electrode at a selected powerratio which is a function of a ratio of the areas of the electrodeswherein the transformer is configured to apply RF power to theshowerhead electrode proportional to a power of a ratio A₁/A₂.
 14. Aplasma enhanced chemical vapor deposition reactor comprising: a firstelectrode configured for supporting a workpiece, the first electrodehaving a first surface area A₁; a second electrode operably associatedwith the first electrode, the second electrode having a second surfacearea A₂ that is less than the first surface area A₁; a single RF powergenerator configured to provide RF power; a transformer having an inputside and an output side with only two output terminals which formindividual connections with any of the reactor's electrodes, the inputside being operably connected with and receiving power from the RF powergenerator, the output terminals being configured to provide RF power toeach electrode at a selected power ratio which is effective to both (a)develop a desired bias relative to a workpiece, and (b) establish andmaintain a plasma processing environment, the transformer beingconfigured to provide RF power to each electrode at a selected powerratio which is a function of an inverse of a ratio A₁/A₂ of the areas ofthe electrodes; and the output side further comprising a plurality ofwindings, individual windings of which can be selectively grounded forvarying the RF power provided to the respective electrodes and theselected power ratio thereof.
 15. The plasma enhanced chemical vapordeposition reactor of claim 14, wherein the reactor is an inductive coilreactor.
 16. The plasma reactor of claim 14, wherein at least one of theelectrodes is configured for supporting a semiconductor workpiece.
 17. Aplasma enhanced chemical vapor deposition reactor comprising: aprocessing chamber; a first electrode inside the chamber and configuredfor supporting a workpiece, the first electrode having a first surfacearea A₁; a second electrode operably associated with the chamber, thesecond electrode having a second surface area A₂ that is less than thefirst surface area A₁; a single RF power generator configured to provideRF power; a transformer having an input side and an output side withonly two output terminals which form individual connections with any ofthe reactor's electrodes, the input side being operably connected withand receiving power from the RF power generator, the output terminalsbeing configured to provide RF power to each electrode at a selectedpower ratio which is effective to both (a) develop a desired biasrelative to a workpiece, and (b) establish and maintain a plasmaprocessing environment inside the processing chamber, the transformerbeing configured to provide RF power to each electrode at a selectedpower ratio which is a function of a ratio A₁/A₂ of the areas of theelectrodes; and the output side further comprising a plurality ofwindings, individual windings of which can be selectively grounded forvarying the RF power provided to the respective electrodes and theselected power ratio thereof, wherein the selected power ratio isconfigured to apply RF power to the second electrode proportional to apower of A₁/A₂.
 18. A plasma enhanced chemical vapor deposition reactorcomprising: a processing chamber; a first electrode inside the chamberand configured for supporting a workpiece, the first electrode having afirst surface area A₁; a second electrode operably associated with thechamber, the second electrode having a second surface area A₂ that isless than the first surface area A₁; a single RF power generatorconfigured to provide RF power; a transformer having an input side andan output side with only two output terminals which form individualconnections with any of the reactor's electrodes, the input side beingoperably connected with and receiving power from the RF power generator,the output terminals being configured to provide RF power to eachelectrode at a selected power ratio which is effective to both (a)develop a desired bias relative to a workpiece, and (b) establish andmaintain a plasma processing environment inside the processing chamber,the transformer being configured to provide RF power to each electrodeat a selected power ratio which is a function of a ratio A₁/A₂ of theareas of the electrodes; and the output side further comprising aplurality of windings, individual windings of which can be selectivelygrounded for varying the RF power provided to the respective electrodesand the selected power ratio thereof, wherein the second electrode is ashowerhead electrode disposed inside the chamber and the selected powerratio is configured to apply RF power to the showerhead electrodeproportional to a power of A₁/A₂.
 19. A plasma enhanced chemical vapordeposition reactor comprising: a processing chamber; a first electrodeinside the chamber and configured for supporting a workpiece, the firstelectrode having a first surface area A₁; a second electrode operablyassociated with the chamber, the second electrode having a secondsurface area A₂ that is less than the first surface area A₁; a single RFpower generator configured to provide RF power; a transformer having aninput side and an output side with only two output terminals which formindividual connections with any of the reactor's electrodes, the inputside being operably connected with and receiving power from the RF powergenerator, the output terminals being configured to provide RF power toeach electrode at a selected power ratio which is effective to both (a)develop a desired bias relative to a workpiece, and (b) establish andmaintain a plasma processing environment inside the processing chamber,the transformer being configured to provide RF power to each electrodeat a selected power ratio which is a function of a ratio A₁/A₂ of theareas of the electrodes; and the output side further comprising aplurality of windings, individual windings of which can be selectivelygrounded for varying the RF power provided to the respective electrodesand the selected power ratio thereof, wherein the second electrode is ashowerhead electrode disposed inside the chamber and wherein theselected power ratio is configured to apply RF power to the showerheadelectrode proportional to (A₁/A₂)⁴.
 20. A capacitive plasma enhancedchemical vapor deposition reactor including: a susceptor electrodewithin the reactor and configured to support at least one semiconductorworkpiece; a shower head electrode within the reactor operably adjacentthe susceptor electrode and configured to provide gaseous reactants intothe reactor, a surface area A₂ of the shower head electrode being lessthan a surface area A₁ of the susceptor electrode; a single RF powergenerator operatively coupled with the susceptor electrode and theshower head electrode and configured to provide RF power theretoeffective to develop a plasma processing environment within the reactorand a desired bias relative to the semiconductor workpiece; and an RFpower splitter comprising a transformer having a primary winding and aseparate secondary winding, the primary winding coupled to the RF powergenerator and the secondary winding coupled to both the susceptorelectrode and the shower head electrode, the RF power splitterconfigured to provide power from the RF power generator to both thesusceptor and the shower head electrode at a selected power ratiobetween the susceptor electrode and the shower head electrode, theselected power ratio being configured to supply a power component to theshowerhead electrode that is a function of an inverse of a ratio A₁/A₂of the areas.
 21. The plasma enhanced chemical vapor deposition reactorof claim 20, wherein the RF power splitter comprises a transformerincluding a center tapped secondary winding having at least two outputterminals, individual output terminals being connected to a respectiveone of the susceptor electrode and the shower head electrode.
 22. Theplasma enhanced chemical vapor deposition reactor of claim 20, whereinthe selected power ratio is adjustable.
 23. The plasma enhanced chemicalvapor deposition reactor of claim 20, wherein the RF power splittercomprises a plurality of variably groundable secondary windings foradjusting the selected power ratio.
 24. A capacitive plasma enhancedchemical vapor deposition reactor including: a susceptor electrodewithin the reactor and configured to support at least one semiconductorworkpiece; a shower head electrode within the reactor operably adjacentthe susceptor electrode and configured to provide gaseous reactants intothe reactor, a surface area A₂ of the shower head electrode being lessthan a surface area A₁ of the susceptor electrode; a single RF powergenerator operatively coupled with the susceptor electrode and theshower head electrode and configured to provide RF power theretoeffective to develop a plasma processing environment within the reactorand a desired bias relative to the semiconductor workpiece; and an RFpower splitter comprising a transformer having a primary winding and aseparate secondary winding, the primary winding coupled to the RF powergenerator and the secondary winding coupled to both the susceptorelectrode and the shower head electrode, the RF power splitterconfigured to provide power from the RF power generator to both thesusceptor and the shower head electrode at a selected power ratiobetween the susceptor electrode and the shower head electrode, theselected power ratio being configured to supply a power component to theshowerhead electrode that is a function of a ratio A₁/A₂ of the areas,wherein the selected power ratio is configured to apply RF power to theshowerhead electrode proportional to a power of the ratio A₁/A₂.
 25. Acapacitive plasma enhanced chemical vapor deposition reactor including:a susceptor electrode within the reactor and configured to support atleast one semiconductor workpiece; a shower head electrode within thereactor operably adjacent the susceptor electrode and configured toprovide gaseous reactants into the reactor, a surface area A₂ of theshower head electrode being less than a surface area A₁ of the susceptorelectrode; a single RF power generator operatively coupled with thesusceptor electrode and the shower head electrode and configured toprovide RF power thereto effective to develop a plasma processingenvironment within the reactor and a desired bias relative to thesemiconductor workpiece; and an RF power splitter comprising atransformer having a primary winding and a separate secondary winding,the primary winding coupled to the RF power generator and the secondarywinding coupled to both the susceptor electrode and the shower headelectrode, the RF power splitter configured to provide power from the RFpower generator to both the susceptor and the shower head electrode at aselected power ratio between the susceptor electrode and the shower headelectrode, the selected power ratio being configured to supply a powercomponent to the showerhead electrode that is a function of a ratioA₁/A₂ of the areas, wherein the selected power ratio is configured toapply RF power to the showerhead electrode proportional to (A₁/A₂)⁴.